Generally, at a dental clinic, several medical appliances such as tweezers, probes, mirrors, and handpieces are used to treat teeth or gums inside a mouth. These appliances are easily contaminated by germs or bacteria contained in blood, spit or tissues of patients, so that preventing other patients from being infected with germs or bacteria by sterilizing the contaminated appliances thoroughly after use is important. Tweezers, probes, and mirrors are relatively cheap, so that it is possible to prepare them in a larger number, gather separately the once used ones, and sterilize using antiseptic solution, or steam or water of high temperature. However, handpieces, connected to a pneumatic device or a laser generator, are not so cheap as to be prepared in a large number and changed whenever being used, and equipped with pneumatic motors and lenses, so that it is impossible to sterilize using steam or water of high temperature, making it hard to sterilize.
An ultraviolet sterilizer shown in FIG. 7 was developed to sterilize such handpieces. The conventional sterilizer 100 like this is equipped in one body with a casing assembly 110 attaching an ultraviolet lamp 112 inside, a drawer 120 withdrawn from and inserted into the front side of the casing assembly 110 to put in dental appliances, and a ventilating fan 130 installed at the inside rear of the case 110 to circulate the inside air through multiple ventilating holes 132.
The sterilizer 100 has problems in that the handle of the drawer 120 is contaminated since the drawer is opened and closed by a contaminated hand to put the handpiece in the drawer 120, and the hands are contaminated by the handle of the drawer 120 when withdrawing the handpiece after sterilization, therefore the handpiece is contaminated when the handpiece is handled by the contaminated hand, together with a problem radiating ultraviolet rays outside.
As depicted in FIG. 8, another conventional sterilizer 200 which solved the problems of the drawer type sterilizer is configured in one body, installing an ultraviolet lamp 212 around a quartz tube 220 established horizontally inside the casing assembly 210 and an opening 230 closed by an ultraviolet barrier 234, which has insertion holes 232 incised in a radial shape, at the outer front of the casing assembly 210 installed with the quartz tube 220.
In case of the sterilizer 200 with an incised ultraviolet barrier 234, the ultraviolet barrier 234 is contaminated by the contaminated handpiece when the handpiece is inserted in the sterilizer, and the handpiece is contaminated by the contaminated ultraviolet barrier 234 again when the sterilized handpiece is withdrawn.